Measurement of quadrupolar coupling with a two-pulse sequence in solid-state N.M.R.

Abstract

The intensity of the central transition of a spin-3/2 system following excitation by two in-phase rf pulses is calculated using the fictitious spin-1/2 operator formalism. Measurement of this line intensity as a function of the duration of the second rf pulse enables the quadrupolar coupling to be determined. The method is illustrated with a study of ⁷Li nuclei in a single crystal of LiTaO₃. For polycrystalline samples the powder average is computed numerically in order to obtain the quadrupolar coupling constant and the asymmetry parameter.